Field
The disclosed concept relates generally to sensors and, more particularly, to piezoelectric sensor assemblies. The disclosed concept also relates to sensor attachment assemblies piezoelectric sensor assemblies. The disclosed concept further relates to electrical systems employing piezoelectric sensor assemblies.
Background Information
Electrical systems often include a plurality of bus bars, and various electrical apparatus, such as electrical switching apparatus (e.g., without limitation, circuit breakers), mechanically coupled and electrically connected to the bus bars.
Some electrical systems employ sensors attached directly to the bus bars, in order to monitor various conditions within the electrical system. In low or medium voltage electrical systems, for example, attachment of such sensors to the bus bars is subject to a variety of issues or problems. It is desirable to provide for relatively quick and easy attachment of the sensors in new system applications, as well as to allow for retro-fit applications. Among other additional considerations are minimizing complexity and cost, ease of assembly and manufacture of the attachment assembly, and avoiding the attachment assembly coming loose, for example during shipment or installation. The sensor and attachment assembly must also be capable of safe and effective operation in relatively high temperature (e.g., up to 135 degrees Celsius or more bus bar temperatures) environments.
By way of example, one sensor application involves the attachment of acoustic sensors to the electrical bus bars of a low to medium voltage electrical system. One prior proposal employs a piezoelectric sensor assembly to detect acoustic signals in order to monitor the bus bars for loose connections. Among other disadvantages, known piezoelectric assemblies are relatively complex in design and employ numerous parts, including a screw assembly to pre-load the piezoelectric element. This adds to the cost and complexity and diminishes reliability. Pre-loading piezoelectric element via the screw assembly also makes it difficult to produce and repeat effective results.
There is, therefore, room for improvement in piezoelectric sensor assemblies, and in sensor attachment assemblies and electrical systems employing the same.